Jaw Fragments Research Articles

Galaxias fossils from Miocene lake deposits, Otago, New Zealand: The earliest records of the Southern Hemisphere family Galaxiidae (Teleostei)

Galaxiid fishes are commonly assumed to exhibit a Gondwanan distribution, but little fossil evidence has been available to support or refute this assumption until now. Here we report on three species of fossil Galaxias, represented by exquisitely preserved, almost entire skeletons, together with jaw and skull fragments, from several Miocene lacustrine deposits in Otago, South Island, New Zealand. These are the only certain Galaxias fossils, and provide unequivocal evidence that the genus was abundant, and taxonomically and ecologically diverse in the New Zealand region before 23 million years ago. One new species, Galaxias effusus, from an Early Miocene diatomite deposit near Middlemarch is described on the basis of low vertebral count, short caudal peduncle, expansive dorsal, caudal and anal fins, rounded to truncate caudal fin, with 15 principal caudal fin rays. The intact skeletons of G. effusus confirm that they inhabited a deep, stratified maar lake with cool, anoxic bottom water. The maar lake was completely landlocked, from sedimentological evidence, and this species must have been non‐migratory. Disarticulated fish jaws and skull fragments from Early Miocene mudstones near Bannockburn are likely to be from a second large species of Galaxias on the basis of dentary, premaxilla and parasphenoid size and morphology. These disarticulated fish remains from a regionally extensive inland lake system indicate decomposition and/or predation in shallow nearshore environments, but we have no evidence yet of migratory behaviour. New specimens of G. kaikorai Whitley from Late Miocene diatomite deposits near Dunedin confirm its morphological similarity to the living G. brevipinnis. The occurrence and diversity of galaxiids in lakes of early and Late Miocene age in southern New Zealand can be explained by either oceanic dispersal across the Southern Hemisphere at any time during the Cenozoic, relict Gondwanan distributions or, most likely, an ancient Gondwanan origin overprinted by Cenozoic dispersal.

NEW TAXA OF TRANSVERSELY-TOOTHED LIZARDS (SQUAMATA: SCINCOMORPHA) AND NEW INFORMATION ON THE EVOLUTIONARY HISTORY OF “TEIIDS”

Abstract New material of polyglyphanodontine lizards from the Late Cretaceous has been found in various localities in western North America. Several transversely oriented teeth representing a new species of Dicothodon were recovered from the Turonian of southern Utah. These specimens necessitate reassignment of Polyglyphanodon bajaensis to Dicothodon (Polyglyphanodon) bajaensis. From the Campanian of Utah, additional teeth and jaw fragments referable to Manangysaurus saueri have been recovered and this species is reassigned here to Peneteius (Manangysaurus) saueri. Also, an isolated tooth referable to Peneteius has been recovered from the Campanian of southern Texas. The results of a phylogenetic analysis support a monophyletic grouping of the transversely-toothed taxa with Bicuspidon as the sister taxon of Polyglyphanodontini new taxon, which is comprised of Polyglyphanodon, Dicothodon, and Peneteius. The phylogenetic analysis also places “teiid” lizards from the Cretaceous of Asia and North America in a...

The Early Permian Branchiosaurids (Amphibia) of Sardinia (Italy): Systematic Palaeontology, Palaeoecology, Biostratigraphy and Palaeobiogeographic Problems

The branchiosaurid fauna from the Is Alinus-lake of Rio su Luda Formation (lithofacies c) in the Perdasdefogu Basin of Sardinia (Italy) includes three species: Melanerpeton eisfeldi, Apateon kontheri and Apateon flagrifer. The same three species are known from Gottlob-lake in the Thuringian Forest Basin of Germany and are interpreted as valid in the sense of the “biospecies” concept, not closely related to each other and most probably reproductive in the same lake. That is a very surprising and convincing conformity of both branchiosaurid faunas: parallel evolution of three different amphibian species in two different areas seems impossible. Gene flow must have existed between the populations of the northern and southern parts of the Variscan mountain chain. Additional findings of three-dimensionally preserved but isolated amphibian bones, such as jaw fragments with pleurodent dentition, have been discovered in limestone of the Rio su Luda Formation (lithofacies d) from the Ortu Mannu section. They belong very probably to those branchiosaurids. Occurrences in both Sardinia and Thuringia require corresponding migration routes for the branchiosaurs, possibly via basins in southern France, the French Massif Central and southern Germany. Possibly all branchiosaurids of these three species are neotenic and referable to the ecomorphological “stream-type” with favourable migration capabilities, as in modern urodelans such as newts and salamanders. The Perdasdefogu Basin of Sardinia is presently the southernmost known occurrence of branchiosaurid amphibians in Europe, and its palaeo-position is of special interest. Sardinia was obviously part of a hydrographical system at the southern flank of the Variscides. No insurmountable migration barrier, such as a marine sound or seaway, existed between Sardinia and Palaeo-Europe, because the same species of obligatorily non-marine amphibians are known from these two areas. The Sardinian occurrence widens significantly the amphibian migration routes described before. On the basis of these amphibians, it is possible to correlate the Rio su Luda Formation of Sardinia with the Goldlauter to Lower Oberhof Formation of the Thuringian Forest reference section by combined use of Melanerpeton eisfeldi and Apateon flagrifer as index species of phylo(morpho)genetic lineages. In synthesis with isotopic ages, this time span is equivalent to the Asselian/Sakmarian transition of the global scale; most likely the Rio su Luda Formation correlates directly with the Upper Goldlauter Formation (Late Asselian).

The ‘condylarth’ Raulvaccia peligrensis (Mammalia: Didolodontidae) from the Paleocene of Patagonia, Argentina

ABSTRACT The Paleocene locality of Punta Peligro (Hansen Member of the Salamanca Formation) in Argentina has yielded not only ‘condylarths’ but also an extraordinary assemblage of therian mammals derived from Laurasian immigrants and non-therian mammals, relicts of the Mesozoic Gondwanan radiation. The materials, a left jaw fragment with the talonid of the second molar and the third molar, and an isolated upper molar, allow the revalidation of Raulvaccia peligrensis considered previously as a junior synonym of Escribania chubutensis. In addition to other characters, Raulvaccia strongly differs from E. chubutensis in its lesser size, the development of the m3 talonid, the presence of a hypocristid, and a postcristid. Originally Raulvaccia and Escribania were considered as Mioclaenidae, Kollpaniinae, together with other ungulates from the Santa Lucía Formation, from the early Paleocene locality of Tiupampa in Bolivia. In contrast to the Tiupampan ‘condylarths,’ Raulvaccia shares derived characters with E. chubutensis, particularly in the upper molars, such as a strong parastyle and the presence of hypocone located close to, but well differentiated from the protocone. These characters support a previous hypothesis which argues for the removal of the Peligran ‘condylarths’ from the more primitive Kollpaniinae, and sustains its relationship to the exclusively South American Didolodontidae. The revalidation of Raulvaccia peligrensis shows that the diversity of placental mammals during the earliest known Paleocene in Patagonia was greater than previously thought, and supports for the early differentiation of the Didolodontidae.

Bicuspidon aff. hatzegiensis (Squamata: Scincomorpha: Teiidae) from the Upper Cretaceous Csehbánya Formation (Hungary, Bakony Mts)

The recently encountered Upper Cretaceous (Santonian) Iharkut terrestrial vertebrate locality has yielded several vertebrate taxa since its discovery. Scincomorphan lizards are also represented in this fauna by several jaw fragments. The most abundant of these is represented by seven dentary fragments and an indeterminate jaw fragment with characteristic teeth. The hypertrophied splenial, the heterodont dentition, the cementum deposition at the bases of the teeth, and the large subcircular resorption pits assign this type to the family Teiidae. The dentition is composed of conical, monocuspid teeth in the mesial region and transversely widened bicuspid teeth in the distal region. This morphology is well known in members of the subfamily Polyglyphanodontinae. Based on their dental morphology the Iharkut finds can be easily assigned to the genus Bicuspidon. This genus is known from two species, B. numerosus Nydam et Cifelli 2002 from the Albian-Cenomanian of Utah (North America) and B. hatzegiensis Folie et...

Positional changes of the lower and upper anterior teeth after surgical correction of mandibular prognathism

To establish the influence of surgical corrections of mandibular prognathism upon the position of the lower and upper anterior teeth (incisors). The changes in position of the lower and upper anterior teeth (incisors) after the surgical correction of mandibular prognathism were analyzed by means of x-ray craniometry in 183 patients (female: n = 110, male: n = 73) in which the correction had been made in accordance with the principles of sagital osteotomy of the mandibular ramus. There were 4 angular and 2 linear parameters determined in the pre- and postoperative tele-x-ray-pictures. The changes of these parameters were tested by means of the parametric statistic tests. The performed surgical procedures did not cause statistically significant changes in the angular parameters. The changes of both linear parameters were thought highly statistically significant. Under the influence of the performed surgical procedures no changes were found in the position of anterior teeth (incisors) in relation to SN and the mandibular plane. They were actually moved along with the medium fragment of the lower jaw and that fragment was moved linearly backwards along the occlusal plane with a practically insignificant rotation in the cranial direction.

A new scincomorph lizard from the Palaeocene of Belgium and the origin of Scincoidea in Europe

Well-preserved jaw fragments and skull bones of a new scincomorphan lizard are described from the continental Hainin Formation (Middle Palaeocene) of the Mons Basin in southwestern Belgium. This taxon, Scincoideus haininensis gen. et sp. nov., is characterised by vermiculate dermal rugosities and represents the earliest formally recognised scincoid in Europe. It differs from cordylids (girdled lizards) by lacking the parietal downgrowth and differs from scincids (skinks) by having robustly built bones and a well-developed lingual cusp on tooth crowns. By its mosaic characters, S. haininensis is considered here as being a basal scincoid lizard close to the origin of cordylids and scincids. Palaeobiogeographic analysis suggests that scincoids were present in Europe from the Palaeocene or maybe even before the Cretaceous/Palaeogene boundary and that they were replaced by modern scincoids such as true scincids and cordylids during the Eocene. The origin of the latter two families in Europe was very likely related with the immigration of the first modern mammals.

A REASSESSMENT OF DIANCHUNGOSAURUS LUFENGENSIS YANG, 1982a, AN ENIGMATIC REPTILE FROM THE LOWER LUFENG FORMATION (LOWER JURASSIC) OF YUNNAN PROVINCE, PEOPLE'S REPUBLIC OF CHINA

Dianchungosaurus lufengensis was erected on the basis of fragmentary isolated jaw elements (a left premaxilla and left and right partial lower jaws) from the Lower Lufeng Formation (Lower Jurassic) of Yunnan Province, China. Yang referred Dianchungosaurus to the Heterodontosauridae (Ornithischia, Ornithopoda), as several features appeared to indicate affinity with the southern African genus Heterodontosaurus . However, reexamination of the type material demonstrates that the holotype specimen of Dianchungosaurus represents a chimaera of prosauropod dinosaur and mesoeucrocodylian remains: the mesoeucrocodylian premaxilla is distinctive and allows the genus to be diagnosed on the basis of several autapomorphic features. Revision of this genus thereby invalidates the only reported occurrence of a heterodontosaurid dinosaur from Asia.

Pleistocene mammals from travertine deposits of the Denizli basin (SW Turkey)

The Denizli basin, which is famous by its modern travertine accumulations such as that of Pamukkale is located at the eastern junction of Büyük Menderes and Gediz grabens in the western Anatolian extensional province. This basin contains large travertine formations, the origin and age of which are still debated. This study briefly recalls the tectonic and stratigraphic context of travertine occurrences and describes some vertebrate remains, which have recently been recorded in travertines. The material mainly consists of jaw fragments referred to Equus aff. suessenbornensis Wüst, 1901, lower teeth and antlers of Dama sp. and some lower teeth of Bos sp. The presence of E. aff. suessenbornensis, indicates a Middle Pleistocene age in agreement with thermoluminescense dating of the travertines.

A giant brachyopoid temnospondyl from the Upper Triassic or Lower Jurassic of Lesotho

Abstract A jaw fragment of a giant temnospondyl from the Upper Triassic or Lower Jurassic of Lesotho (southern Africa), initially regarded as a Triassic mastodonsaurid because of its size, is redescribed in detail and considered to be a member of the Brachyopoidea (Brachyopidae + Chigutisauridae sensu Warren and Marsicano [2000]) based on its dental morphology, presence of a well-developed ectopterygoid tusk, and the concavity of the ventral margin of the skull in lateral view. Recognition of the specimen as a brachyopid, rather than as a chigutisaurid, is of palaeobiogeographical significance in representing one of the youngest known brachyopids from Gondwana. The Lesotho specimen is also of palaeobiological interest in that an estimate of its overall size indicates that it represents one of the largest amphibians sensu lato ever known.

Facelift Supports Skull's Status as Oldest Member of the Human Family

PALEOANTHROPOLOGYFresh fossils of teeth and jaw fragments of Sahelanthropus tchadensis , plus a state-of-the-art analysis of a three-dimensional virtual reconstruction, show that the 7-million-year-old skull nicknamed Toumai is indeed a hominid and that he might have walked upright.

The Neogene mammalian faunas of Ertemte and Harr Obo in Inner Mongolia (Nei Mongol), China. — 13. The generaMicrotodon andAnatolomys (Rodentia, Cricetidae)

New extensive tooth material of late Miocene and early Pliocene microtoid cricetids (Mammalia, Rodentia) from Inner Mongolia (PR of China) is described from their type locality and adjacent area. It belongs toMicrotodon atavus and the more rareAnatolomys teilhardi, which both were known so far only by a few jaw fragments. There are now more than 2500 isolated teeth available which document the high morphological variation of single tooth structures. In contrast toAnatolomys, which had not previously been reported with certainty from Europe, but may be represented by “Wartamys”kowalskii from Podlesice (Poland),Microtodon is widespread in Europe. However,Microtodon material was treated mostly as a separate genus: “Baranomys”. The high morphological variation inMicrotodon teeth from Ertemte clearly demonstrates that the European “Baranomys” is without any doubt identical to the East AsianMicrotodon. The European genera “Celadensia” and less probablyBjornkurtenia also may be identical with one of the East Asian microtoid cricetids.

Lusitanisuchus, a new generic name for Lisboasaurus mitracostatus (Crocodylomorpha: Mesoeucrocodylia), with a description of new remains from the Upper Jurassic (Kimmeridgian) and Lower Cretaceous (Berriasian) of Portugal

Lusitanisuchus mitracostatus is a small mesoeucrocodilian crocodylomorph from the Upper Jurassic (Kimmeridgian) of Guimarota–Leiria in Portugal, which was originally described as an anguimorph lizard (Lisboasaurus mitracostatus Seiffert, 1970) based on jaw fragments and isolated teeth. A recent reexamination of the crocodylomorph material of Guimarota yielded new skull and dentary remains assignable to Lusitanisuchus mitracostatus. The new skull material not only enables for the first time a skull reconstruction of this taxon, but also leads to renaming and reclassifying Lisboasaurus mitracostatus. Teeth of Lusitanisuchus are also reported from the locality Porto Dinheiro–Lourinhã, Early Cretaceous (Berriasian) of Portugal. The presence of this crocodylomorph taxon in two Portuguese localities suggests its occurence in the Lusitanian Basin during the Kimmeridgian to the Berriasian.

Crocodilian remains from the Upper Eocene of Dor-El-Talha, Libya

Study of undescribed material from Dor-El-Talha (Libya, Upper Eocene) reveals the existence of at least three different crocodilian taxa at this locality: a gavialid, a tomistomine and a mesosuchian represented by just one amphicoelous vertebra. Most of this material is fragmentary and it includes mainly fragments of snouts and lower jaws. The crocodilian fauna from this locality shows similarities with that from the contemporaneous El Fayum locality (Egypt).

Arcticanodon dawsonae, a primitive new palaeanodont from the lower Eocene of Ellesmere Island, Canadian High Arctic

A new genus and species of palaeanodont, Arcticanodon dawsonae, is based on a single lower jaw fragment from lower Eocene (Wasatchian) strata of the Margaret Formation, Eureka Sound Group, on central Ellesmere Island, Nunavut. The new taxon is more derived than early Paleocene Escavadodontidae, but lacks derived traits of Metacheiromyidae. It is therefore most similar to primitive epoicotheriids, although the similarities are essentially in plesiomorphic features. Consequently, Arcticanodon dawsonae is classified as Palaeanodonta, incertae sedis, pending discovery of more complete specimens.

A NEW DIADECTID (DIADECTOMORPHA), OROBATES PABSTI, FROM THE EARLY PERMIAN OF CENTRAL GERMANY

A new genus and species of the herbivorous Diadectidae, Orobates pabsti, is described on the basis of several specimens, including two complete, articulated skeletons, a skull with partial postcranium, a partial skull, and a dentigerous jaw fragment. All were collected from the Lower Permian (Wolfcampian) Tambach Formation, lowermost formational unit of the Upper Rotliegend of the Bromacker quarry locality in the midregion of the Thuringian Forest near Gotha, central Germany. A combination of autapomorphic and plesiomorphic character states clearly distinguishes O. pabsti from all other well-known members of Diadectidae and identifies it as the sister taxon to all other diadectids.The description of Orobates pabsti expands further our understanding of the Late Pennsylvanian-Early Permian Diadectidae and records the earliest specialization of tetrapods to high-fiber herbivory.On the basis of paleobiological and paleoenvironmental data only one other Early Permian locality is comparable to the Bro-macker locality, the somewhat younger (Leonardian) fissure fill deposits at Richards Spur, southeastern Oklahoma. This further supports the previously proposed hypothesis, based on similar grounds, that the vertebrates of both localities may have been part of a widespread, terrestrial upland faunal assemblage during the Early Permian.

A euprimate skull from the early Eocene of China.

The debut of undoubted euprimates (primates of modern aspect) was in the early Eocene, about 55 Myr ago. Since their first appearance, the earliest euprimates can be distinguished as Cantius, Donrussellia and Teilhardina. Nonetheless, the earliest euprimates are primarily known from isolated teeth or fragmentary jaws. Here we describe a partially preserved euprimate skull with nearly complete upper and lower dentition, which represents a new species of Teilhardina and constitutes the first discovery of the genus in Asia. The new species is from the upper section of Lingcha Formation, Hunan Province, China, with an estimated age of 54.97 Myr ago. Morphology and phylogeny analyses reveal that the new species is the most primitive species of Teilhardina, positioned near the root of euprimate radiation. This discovery of the earliest euprimate skull known to date casts new light on the debate concerning the adaptive origin of euprimates, and suggests that the last common ancestor of euprimates was probably a small, diurnal, visually oriented predator.

Chapter 19

Partial skeletons, including jaw fragments, collected by Richard H. Tedford and colleagues at Lake Pinpa in the Callabonna Basin of northeastern South Australia, represent a new species of the putative wynyardiid marsupial Muramura. The new species is slightly smaller and more gracile than its congener M. williamsi from the roughly contemporaneous Etadunna Formation of the Lake Eyre Basin.

Isectolophus (Mammalia, Perissodactyla) from the Eocene of the Zaysan Basin, Kazakstan and its biochronological significance

ABSTRACT We describe a skull and fragments of lower jaws of a ceratomorph perissodactyl from the Arshantan (Eocene) strata of the Zaysan Basin, eastern Kazakstan, and refer these specimens to Isectolophus latidens (Osborn, Scott, and Speir, 1878). The material from the Zaysan Basin is indistinguishable from the holotypes of Isectolophus bogdulensis Reshetov from Mongolia and Homogalax reliquius Qi from China. These two species are junior subjective synonyms of I. latidens. The presence of I. latidens, known also from Bridgerian strata of North America, in Asian deposits of Arshantan age provides further support for a correlation between the Arshantan and the Bridgerian land-mammal “ages.”

Lizards from the Lower Cretaceous (Aptian–Albian) Antlers and Cloverly Formations

ABSTRACT Recent discoveries from the Aptian–Albian Antlers (Oklahoma) and Cloverly (Montana, Wyoming) formations provide significant additions to the Early Cretaceous record of lizards in North America. The lizards from the Antlers Formation include two teiids (one named), an anguimorphan, and a series of fragmentary jaws with “paramacellodid”-like teeth. The lizards from the Cloverly Formation include a new species of Paramacellodus and many indeterminate jaw fragments. The apparent lack of shared lizard taxa between the two units calls into question their temporal equivalence, which is based on similarity of dinosaur taxa. Although apparently distinct, the lizard faunas of both units are very similar to that of the Late Jurassic Morrison Formation in being composed primarily of “para-macellodid” or “paramacellodid”-like taxa. It appears that there was a period of relative stasis in the evolution of lizards in North America between the Late Jurassic and Aptian–Albian, paralleling a similar trend in Europe between the Late Jurassic and the Barremian (or later). Reported lizards from the Aptian-Albian of Mongolia present a level of taxonomic diversity much different than that of the same time period in Oklahoma, Montana, and Wyoming, but more like that of the Late Cretaceous of North America, suggesting that taxonomic groups common to the Late Cretaceous and Tertiary occurred earlier in Asia than in North America.